The radar / radar telescope at the Arecibo Observatory in Puerto Rico was a 1,000-foot-diameter dish located in a valley, with 900 tons of electronic gear hanging 450 feet above the plate suspended by three-tower cables.
Last August, an auxiliary cable slipped from its outlet and broke a 100-foot gap in the reflector plate. In November, while an engineering team was trying to work out a plan to repair the damage, a three-inch main steel cable broke. The team soon discovered that the main cable failed at about 60% of its estimated minimum breaking strength during quiet weather. This made them suspect that other cables could also be weaker than expected. Apparently, they were right, as the plate collapsed on December 1st.
The already damaged radar board at the Arecibo Observatory in Puerto Rico collapsed on December 1 after two cable breaks over the past four months.University of Central Florida
After the second cable failure, an engineering consulting firm came in that determined that given the risk of more cable failures, telescope repairs would be unsafe. Even stress tests to get more data on the remaining cables were considered too risky. The firm finally recommended a controlled demolition to eliminate the dangers of an unexpected collapse.
This image shows the damage caused by a failed cable a few months ago on the plate.
Two other consulting scales were hired to assess the situation. It was thought that stabilization was possible and needed to be done immediately. The other agreed that there was no way to verify the stability of the structure securely and advised against anyone being on the platforms or towers of the telescope.
The National Science Foundation (NSF, owner of the telescope) and the University of Central Florida (which manages its day-to-day operations) had decided to play it safe and tear down the 57-year-old structure. Demolition engineers were working on a controlled dismantling that could involve helicopters and explosives, before it was destroyed.
A drone view of a damaged cable at the Arecibo Observatory after a second cable failed.Arecibo Observatories
Closing the entire facility would be a major setback for the hundreds of scientists who use it and postgraduate students who train there. It would also close one of Puerto Rico’s top tourist attractions. It usually attracts more than 90,000 visitors a year.
The observatory staff will do this work with scientists who have already scheduled the use of the telescope to move their research projects whenever possible. But the Arecibo telescope and its radar capability were unique and widely used to study asteroids close to Earth and other objects in the solar system. So while some of Arecibo’s science will be transferred, administrators said, some won’t.
The NSF says that even though the telescope is down and it is unlikely to do so will be replaced, the visitor center will continue to be used, an in situ atmospheric science instrument and a LIDAR facility, and a second atmospheric tool that will analyze cloud cover and precipitation on the neighboring island of Culebra.
Milestones and discoveries of the Arecibo Observatory
The Arecibo Observatory has been used to make a lot of celestial discoveries since it went online in 1963.
- Mercury determined it rotated once every 59 days, not every 88 (1964).
- He discovered the first neutron star (1968).
- He discovered the first binary pulsar, which won a Nobel Prize (1974).
- He transmitted the message Arecibo (1974).
- Discovered the first pulsar of milliseconds (1982).
- First use of radar for the image of an asteroid (1989).
- First discovery of planets around another star (1990).
- Radio emissions detected by a dwarf star T (2011).
The telescope was originally built for military intelligence uses. It is said to have been used to locate Soviet radar installations by detecting their signals bouncing off the moon.
Decoding the Arecibo message
In 1974, a group of scientists composed a coded message binary symbols, the message Arecibo, they wanted to send into space. The supposed goal was to contact other beings and let them know something about us, if they could decode the short, cryptic message.
In fact, it was more of an advertising ploy to promote technology and human capabilities and the United States than a shout out to foreigners. They transmitted the message from the Arecibo Observatory and directed it to M13, a cluster of globular stars 25,000 light-years away in space. They chose M13 only because it was large, relatively close and would be visible in the sky when the transmission was scheduled during a ceremony to mark a remodeling of the telescope on November 16th.
The entire message consisted of 1,679 binary digits, approximately 210 bytes. The number 1,679 was chosen because it is a semiprime (the product of two prime numbers) and can be arranged in 73 rows and 23 columns. The alternative arrangement, of 23 rows and 73 columns, creates an unintelligible nonsense. The observatory transmitted the message at 2,380 MHz modulated by changing the frequency to 10 Hz, with a power of 450 kW. The “ones” and “zeros” were transmitted by frequency shift at the rate of 10 bits per second. The total broadcast took less than three minutes.
The Arecibo message.
The message consists of several “binary clues” about human life. The original message had no color; it was in black and white. From above:
- Blank: the numbers from one to ten.
- In purple: the atomic number of hydrogen, carbon, nitrogen, oxygen and phosphorus, the elements that make up DNA.
- In green: formulas for sugars and the bases of DNA nucleotides.
- Blank: The number of nucleotides in DNA.
- In blue: The double helix of DNA structure.
- In red: image of a human.
- In blue and white: the height of a human. These “messages” can be difficult to decode. For example, in this one, the horizontal white blocks are a binary representation of the number 14. Multiplying 14 by the wavelength of the message (126 mm) produces 1,764 millimeters, or 1.7 meters, the average height d ‘a man.
- Blank: human population of the Earth.
- In yellow: A graph of the solar system with the planet originating the message above the others and just below the red human figure.
In purple: A graph of the Arecibo radio telescope with an M below to indicate that the antenna is concave.
In blue and white: Tthe diameter of the transmitting antenna.